Carbocyclic analogues of nucleosides are described in European Patent Application Publication No. 345,076 published Dec. 6, 1989 as being useful as pharmaceuticals in the treatment of viruses, especially Herpetoviridae. A particular compound described is (1'S, 3'S, 4'S)-2-amino-1,9-dihydro-9-[3,4-dihydroxy-3-(hydroxymethyl)-1-cyclopentyl] -6H-purin-6-one of the following formula (I): ##STR2##
European Patent Application Publication No. 349,242 published Jan. 3, 1990 assigned to the Wellcome Foundation teaches 6-substituted purine carbocyclic nucleosides and Example 45 provides a synthesis of (.+-.)-9-[3-(hydroxymethyl)-3-cyclopenten-1-yl)guanine (racemic compound of formula (X)). A process for synthesizing 2-amino-1,9-dihydro-9-[2,3-dihydroxy-4-(hydroxymethyl)-1-cyclopentanyl]-6H -purin-6-one is taught in U.S. Pat. No. 5,110,926 using hydrolysis as a final step. U.S. Pat. No. 5,233,041 teaches the synthesis of (1'S, 3'S, 4'S)-2-amino-1,9-dihydro-9-[3,4-dihydroxy-3-(hydroxymethyl)-1-cyclopentany l]-6H-purin-6-one using a Swern oxidation. U.S. Pat. No. 5,126,452 teaches the synthesis of (-)-carbovir, 2-amino-1,9-dihydro-9-[3-(hydroxymethyl)-1-cyclopentenyl]-6H-purin-6-one.